Ozone tagging velocimetry using narrowband excimer lasers

Ozone tagging velocimetry (OTV) is a nonintrusive time-of-flight velocity measurement method. It is composed of a write step, where a 193-nm pulsed excimer laser creates an O3 line through O2 uv absorption, and a subsequent read step, where a 248-nm excimer laser photodissociates the O3 and fluoresces the vibrationally excited O2 product, indicating the tag line displacement. Instantaneous OTV images and velocity measurements were obtained for the first time in airflows at room temperature.